Free UUID v4 and v7 Generator
Generate secure random UUID v4 or sortable UUID v7 identifiers, one or a thousand at a time, in the exact format your code or database needs.
UUID v4 and v7 Generator: Generate secure random UUID v4 or sortable UUID v7 identifiers, one or a thousand at a time, in the exact format your code or database needs. It is free, needs no sign-up and runs in your browser. How to use it: 1) choose version 4 or 7 and how many you need; 2) pick a format: uppercase, no dashes, braces, JSON, CSV or SQL; 3) copy or download the list, or inspect an existing UUID. A UUID (also called a GUID) is a 128-bit identifier written as 32 hexadecimal characters in the pattern 8-4-4-4-12. Both versions here use your browser’s cryptographically secure random generator, so the chance of a collision is negligible.
How the UUID generator works
A UUID (also called a GUID) is a 128-bit identifier written as 32 hexadecimal characters in the pattern 8-4-4-4-12. Both versions here use your browser’s cryptographically secure random generator, so the chance of a collision is negligible.
Version 4 or version 7
| Version | Contents | Best for |
|---|---|---|
| v4 | 122 random bits | Public IDs that should not reveal timing |
| v7 | 48-bit Unix time in milliseconds plus random bits | Database primary keys and logs |
Version 7, defined in RFC 9562, sorts by creation time. That keeps database indexes compact and inserts fast. When you generate many v7 UUIDs in the same millisecond, a counter keeps the list in strict order.
Formats
Output can be lowercase or uppercase, with or without dashes, and wrapped in braces as used by Microsoft tools. You can export one per line, as a JSON array, a CSV column or SQL values ready for an INSERT statement.
Inspector
Paste any UUID to see its version and variant. For versions 1, 6 and 7 the inspector also reads the timestamp inside and shows when the UUID was created.
Limitations
Up to 1000 UUIDs per batch. Version 7 reveals the creation time, so avoid it where that is sensitive. Name based versions 3 and 5 are not generated.
UUID Generator FAQs
What is the difference between UUID v4 and v7?
Version 4 is completely random. Version 7 starts with the current time in milliseconds followed by random bits, so new IDs sort after older ones. Use v7 for database keys to keep indexes efficient, and v4 when you do not want an ID to reveal when it was created.
Can two UUIDs ever be the same?
In theory yes, in practice no. A version 4 UUID has 122 random bits, so you would need to generate about a billion UUIDs every second for decades before a collision became likely. This tool uses the browser’s secure random generator, which gives that full randomness.
Is a GUID the same as a UUID?
Yes. GUID is Microsoft’s name for the same 128-bit identifier. Microsoft tools often show GUIDs in uppercase and inside curly braces, such as {3F2504E0-4F89-11D3-9A0C-0305E82C3301}. Use the uppercase and braces options in this generator to produce exactly that format for Windows, .NET or SQL Server.
Should I use UUIDs as database primary keys?
UUIDs let you create IDs on any device without asking the database, which helps with offline apps and merging data. Random v4 keys can slow inserts on large tables because they scatter across the index. Time ordered v7 keys avoid that problem and are the better choice for new tables.
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